Granular fertilizers can be coated to reduce dust production and to slow the release of nutrients into the soil over time decreasing the environmental risk. If the fertilizer nutrients are released too quickly plants can be harmed due to the nutrient loss in the soil by leaching to underground and/or through volatilization to atmosphere, degradation (chemical, photochemical and biological), adsorption, or land immobilization. Coating materials typically have limited solubility in water—this limited solubility being essential to the slow release of nutrients over time.
Typical coatings involve polymers, petroleum products, oils, and sulfur containing materials. Each of these coatings suffer from one or more drawbacks such as cost, being environmentally unfriendly, and increasing soil salinity. There remains a need in the art for improved coatings for granular fertilizers.